1. Field of the Invention
The present invention relates to a method for discovering a network device, and more particularly to a method for executing a discovery procedure in a Data Link Layer (i.e. Layer 2) via a Network Management Server (NMS) within a Local Area Network (LAN) system to discover other network devices within the LAN.
2. Description of the Prior Art
Presently, due to people needing portability from their electronic information apparatus and the real-time transmission of electronic information, various network communication functions have become one of the prerequisites when a consumer wants to buy an electronic information apparatus. For a communication system of Local Area Network (LAN), it is important for manufacturers to develop how to discover and identify various network devices in a network system to manage the network devices.
Nowadays, a traditional method for discovering a network device in a traditional wired or wireless network system is generally provided with a Network Management Server (NMS) for executing a discovery procedure in a Layer 3 (i.e. a network layer) of an Open System Interconnection 7-Layer Model (i.e. OSI 7 Layers Model) in order to discover all network devices which are normally working in the network system. In the traditional method, all of the network devices must firstly obtain only one effective IP address from a Dynamic Host Configuration Protocol (DHCP) server, and then define the IP address as an identification. After this, the NMS broadcasts a discovery packet. Once any one of the network devices in the network system receives the discovery packet, said network device will send a response packet including corresponding information, such as a corresponding IP address, back to the NMS. Therefore, the NMS will identify the identification of each of the network devices according to the information, such as the IP address, included in the response packet for the purpose of managing the network devices.
However, the traditional method for discovering the network device as described above still has the following disadvantages:
(1) In the traditional method, all of the network devices must firstly obtain only one effective IP address corresponding to each of the network devices before starting the discovery procedure. In other words, if one of the network devices can not obtain its corresponding IP address in advance, the discovery procedure will not be executed.
(2) In the traditional method, a DHCP server is essential in the network system in order to obtain only one effective IP address, so as to increase additional hardware cost and inevitably expand corresponding software and network framework, wherein the additional hardware cost is only used for the purpose of allocating IP addresses. For some compact network device only having limited operation ability and hardware support, it is relatively inefficient to execute an IP address processing procedure, even though the compact network device is unsuitable to execute the traditional method.
(3) Most of the network devices are pre-set with a predetermined default IP address after fabrication, and the network devices fabricated by the same manufacturer (even different manufacturers) are generally pre-set with the same predetermined default IP address. If two or more network devices having the same predetermined IP address are discovered in a discovery procedure, the NMS will be confused so that the network system may be instable, or need to be additionally noticed and adjusted by a network administrator.
In addition to the traditional method for discovering a network device as described above, there is still a traditional method for executing a discovery procedure of a network device by using a superior layer of a network layer communication protocol or by using more complicated packet content, wherein the later traditional method is not only complicated, but also basically has the same or similar disadvantages as that of the former traditional method as described above, which defines the IP address as an identification of the network device.
Furthermore, although there is a further conventional method for detecting a network device via a Media Access Control (MAC) address of the network device, such as the communication protocol of Operations And Maintenance (OAM), the conventional method is only used to detect or test the operation of the network device, but not to execute a discovery procedure.
It is therefore tried by the inventor to develop a method for discovering a network device to solve the problems existing in the traditional method as described above.